The Efficacy of Plant Inhibitors as Used against Structural Mild Steel Corrosion: A Review

MS acceptability for nowadays structural construction is premised on its availability and low cost. However, due to MS poor corrosion resistance, most especially in acidic and alkaline environments, there have been increasing concerns about its use. The use of inhibitors, as proposed by different researchers, mitigates MS CR, thus reducing the economic losses experienced by all chief users of this alloy. In recent years, scientists have focused on green inhibitors obtained from plant, fruit and vegetable extracts, and essential oils. Besides being environmentally friendly, in terms of corrosion resistance, plant extracts are becoming increasingly important, due to their low cost and toxicity, and high availability. Additionally, they are rich in organic compounds with polar atoms, such as O, P, S and N, containing multiple bonds in their molecules, through which they can adsorb onto the metal surface, forming a protective film, by various adsorption isotherms. This paper provides a review on research works done so far on MS corrosion control by naturally occurring plant extracts as corrosion inhibitors, in both acidic and alkaline environments, where this alloy is mainly applied.